With the recent advent of increased popularity of motorcycles, both as sports vehicles and vehicles for basic transportation, an interest in motorcycle sidecars has been renewed. The substantial increase in passenger and loadcarrying capacity provided by connecting a sidecar to a motorcycle enhances the utility of the motorcycle and adds an element of stability, the lack of which might otherwise discourage would-be users or purchasers of motorcycles. Further, if a sidecar is readily detachable and attachable to the motorcycle, the aforementioned advantages of a sidecar can be enjoyed while still permitting use of the motorcycle separate from the sidecar with the attendant improvement in maneuverability and handling on occasions when the advantages provided by a sidecar are not needed.
The fundamental elements of a typical sidecar comprise a frame, means for securing the frame to a motorcycle, a body supported by the sidecar frame and a sidecar wheel and associated axle attached to the frame on the side opposite the motorcycle. A suspension system for absorbing road shock may also be considered a fundamental element.
Preferably, a sidecar frame should be lightweight and readily connectible with the motorcycle, while having the necessary strength and rigidity characteristics needed to withstand the various loads and stresses which may be applied to it during normal usage. It is further desirable that the frame be adaptable for mounting to different makes of motorcycles and that it facilitates use of an easy and simple means to absorb road shock. Needless to say, the fewer the number of frame elements and the lesser the amount of material needed for each frame element, the less expensive will be the manufacturing costs of the frame.
Known sidecar frames have substantially failed to achieve many, if not all, of the objectives noted above. Specifically, such sidecar frames have included a large number of frame elements and used elements of large size and strength. This has added to the weight of such frames, detracted from the ease of interconnection of the frame and motorcycle and otherwise presented ancillary disadvantages.